如何防止继承类实例

Question

I want to force any class not to be able to create a new instance if it inherits a specific base class, so how this base class should look like?

Answer 1

The following code is in java. just to give you an Example

Base class has an exception on the constructor.

public class BaseClass 
{
    public BaseClass()
    {
        throw new AssertionError();
    }
}

The child class extending the base class but if you create an object of it it will give u an exception.

public class MainClass extends BaseClass 
{
    public MainClass()
    {

    }

    public static void main(String[] args) {
        MainClass c = new MainClass();
    }
}

Answer 2

You want to seal your base class.

public sealed class BaseClass
{
    public BaseClass(){};
}



public class SubClass : BaseClass
{
    public SubClass(){};
}

This will throw a compiler error because you cannot inherit from a sealed base.

Answer 3

You can't specify that in the baseclass, any deriving class is self responseable, if it wants to present the ability to be derived from, than you can't do anything about it.

Answer 4

you can declare the base class as const - that way other classes cant extend it.

Answer 5

You can't do this. Please specify why you want to do this.